1. Field of the Invention
Machines for boring and finishing cylindrical holes, such as engine cylinder bores, use a tool having abrasive strips mounted on a cylindrical body. As these tools wear, they are generally adjusted radially outward to compensate for the depletion of the abrasive surface. The wear compensating adjustment mechanism forms part of the tool body and comes in many shapes and sizes, for example the tool shown and described in U.S. Pat. No. 4,075,794. These tools consist of a mandrel which connects to the machine spindle at one end and is constructed with an abrasive head at the other. A connecting rod connects to an adjustment mechanism within the abrasive head to bias the abrasive elements radially outward against the work piece. The adjustment can be accomplished automatically as shown in the '794 patent or manually as shown in the reference Gross, U.S. Pat. No. 2,787,865.
The particular tools, shown in the above referenced patents, are used in honing machines for the construction of precision bores, such as piston cylinders in automotive engines, transmission pinion gears, and similar applications. In the past, such machines have been dedicated to specific tasks in association with particular production runs. With the onset of modern manufacturing concepts such as “Just in Time Manufacturing”, lean manufacturing, and other inventory reduction methods, there is a need to apply flexible machining systems to the tasks that were previously performed by dedicated machinery. Flexible machine systems generally employ computer numerically controlled (CNC) equipment capable of performing multiple varied operations on multiple workpieces. It is a purpose of this invention to provide a honing tool for use with CNC machinery.
A common feature of CNC machines is the use of through the tool coolant dispersion for lubricating and cooling the abrasives during use. It is another purpose of this invention to utilize the cooling fluid of CNC machines to provide actuation of the abrasive stone adjustment.
One attempt to utilize coolant fluid to actuate the adjustment of abrasive elements is shown in U.S. Pat. No. 5,800,252. In this system a revamped tool is constructed which provides a supply of pressurized liquid down the length of the mandrel to the underside of the abrasive elements. This design requires a specially designed fluid supply and tool. It is a purpose of this invention to provide a honing tool for CNC machines that can be simply retrofitted to provide fluid actuation of the abrasive elements.
In certain systems, the honing tool is used in a single pass process. In such processes the abrasives are not collapsed, but remain at size and are expanded to compensate for wear. The tools used in a single pass process generally utilize a different adjustment mechanism then is described above. The feed rod of such a mechanism is threaded and driven in rotation. Rotation in the threads moves the feed rod axially downward to expand the abrasive elements as needed. Such actuation is shown in the U.S. Pat. Nos. 4,075,794 and 2,787,865 cited above. It is a purpose of this invention to provide fluid actuation of a threaded adjustment mechanism.